CN108058057A - Shock absorber and semi-active type shock absorption method using same - Google Patents

Abstract

The present invention discloses a shock absorber and a semi-active vibration reduction method using the shock absorber. The shock absorber is used to be installed on a rotating module. The shock absorber includes a screw, a displacement adjustment member, a first spring, a second spring and a mass block. The displacement adjustment member is screwed to the screw in a non-rotatable manner. The mass block is located between the first spring and the second spring, and connects the first spring and the second spring. The first spring is located between the mass block and the displacement adjustment member and connects the mass block and the displacement adjustment member, and the elastic coefficient of the first spring and the elastic coefficient of the second spring are both nonlinear.

Description

Shock absorber and semi-active vibration reduction method using the same

technical field

The invention relates to a shock absorber and a vibration reduction method using the same, and in particular to a shock absorber and a semi-active vibration reduction method using the same.

Background technique

The cutting performance of a machine tool varies with depth of cut and speed. When the cutting condition falls in the unstable area of the cutting stability diagram, it means that the cutting is in an unstable state, which will cause chatter. In actual processing, the cutting steady state diagram is generally referred to to avoid the unstable zone, which leads to the passive limitation of the operating range of the machine tool.

Therefore, it is urgent to propose a new technology to improve the aforementioned problems.

Contents of the invention

Therefore, the purpose of the present invention is to provide a shock absorber and a semi-active vibration reduction method using the same, which can improve the existing problems.

To achieve the above purpose, according to an embodiment of the present invention, a shock absorber is proposed. The shock absorber mechanism is used to be installed on a rotating module. The shock absorber includes a screw rod, a displacement adjusting part, at least one first spring, at least one second spring, a mass block, a shell, an outer cover and a connecting part. The displacement adjusting part is screwed to the screw rod. The mass blocks are located between the first spring and the second spring, are respectively connected to the first spring and the second spring, and are passed through by the screw rod. The shell accommodates the screw rod, the displacement adjusting part, at least one first spring, at least one second spring and mass block. A cover is attached to one end of the housing. The connecting piece is connected to the other end of the casing and used for fixing to the rotating module. Wherein, at least one first spring is located between the mass block and the displacement adjustment member and is connected to the mass block and the displacement adjustment member, and the elastic coefficients of the at least one first spring and the at least one second spring are nonlinear.

According to another embodiment of the present invention, a semi-active vibration reduction method is proposed. The semi-active vibration damping method includes the following steps. Sensing the processing condition of a rotating module, wherein the rotating module is equipped with a shock absorber as mentioned above; judging whether the rotating module flutters; if the rotating module flutters, according to a relationship between displacement and frequency, determine when the flutter occurs A displacement corresponding to a working frequency; and, driving the screw rod of the shock absorber to rotate to drive the displacement adjusting part to displace the displacement.

In order to have a better understanding of the above-mentioned and other aspects of the present invention, the preferred embodiments are specifically cited below, together with the accompanying drawings, and described in detail as follows:

Description of drawings

FIG. 1 is a schematic diagram of a shock absorber installed on a machine tool according to an embodiment of the present invention;

Fig. 2 is a frequency response diagram of the machine tool of Fig. 1;

Fig. 3 is a cutting steady state diagram of the machine tool of Fig. 1;

Fig. 4 is a sectional view of the shock absorber of Fig. 1;

Fig. 5A is a diagram showing the relationship between the displacement and force of the displacement adjustment member in Fig. 4;

Fig. 5B is a relationship diagram between the working frequency and the response of the machine tool in Fig. 4;

Fig. 6 is an equivalent system diagram of the machine tool equipped with a shock absorber in Fig. 1;

FIG. 7 is a flowchart of a vibration reduction method according to an embodiment of the present invention.

Symbol Description

10: machine tools

11: Turn the module

12: Shaft

13: Fixed seat

13b: lower surface

14: Sensor

15: Knife

100: shock absorber

105: outer cover

105a: through hole

110: connector

110s: Mounting surface

115: shell

120: screw

121: first end

122: second end

125: Displacement adjustment piece

130: first spring

130': spring

135: second spring

140: mass block

145: drive mechanism

1451: transmission mechanism

1452: Motor

1453: Worm Gear

1454: Worm

150: Adapter

150s: surface

155: Controller

160: Bearing

a, b, c: points

C: curve

Cs, Ct: Damping

D1: Adjust direction

f: working frequency

fr: resonance frequency

Ks, Kt: coefficient of elasticity

Mt, Ms: mass

R, Ra, Ra': Response

R1: Relationship between displacement and frequency

S110, S120, S130, S140: steps

Sa, Sb, Sc: slope

T: speed

t: depth of cut

W1: Workpiece

Detailed ways

Please refer to FIG. 1 , FIG. 2 and FIG. 3 , FIG. 1 is a schematic diagram of a shock absorber 100 installed on a machine tool 10 according to an embodiment of the present invention, FIG. 2 is a frequency response diagram of the machine tool 10 in FIG. 1 , and FIG. 3 is a cutting steady state diagram of the machine tool 10 of FIG. 1 .

As shown in FIG. 1 , the machine tool 10 at least includes a rotating module 11 , and the shock absorber 100 is mounted on the rotating module 11 , for example. The rotating module 11 includes a rotating shaft 12 and a fixing base 13 , the rotating shaft 12 is connected to the fixing base 13 and is rotatable relative to the fixing base 13 . The tool 15 can be mounted on the rotating shaft 12 and rotated by the rotating shaft 12 to cut the workpiece W1. Furthermore, the machine tool 10 is, for example, a milling machine or another machine tool in which machining is performed with rotating tools. In addition, the shock absorber 100 is not limited to be mounted on a machine tool, and can also be mounted on a mechanical device with rotating elements, such as a fluid machine with rotating vanes.

The shock absorber 100 can be mounted on the fixing seat 13 of the rotating module 11 . As shown in FIG. 1 , the shock absorber 100 is installed on the fixing base 13 through the adapter 150 . There is a fixed relationship between the shock absorber 100 and the fixed seat 13 , that is, there is no relative movement between the shock absorber 100 and the fixed seat 13 , so that the damping coefficient or elastic coefficient between the shock absorber 100 and the fixed seat 13 can be avoided. In addition, although not shown in the figure, the adapter 150 can be detachably fixed to the fixing base 13 by a fixing member, such as a screw, a tenon, etc. The adapter 150 provides a surface 150s that can match the installation surface 110s of the shock absorber 100 , so that the shock absorber 100 can be firmly connected to the adapter 150 . When the mounting surface 110 s of the shock absorber 100 is a flat bottom surface, the surface 150 s of the adapter 150 is a matching plane to allow the connecting member 110 of the shock absorber 100 to be firmly mounted on the adapter 150 . In an exemplary embodiment, the adapter 150 can be part of the shock absorber 100 or part of the machine tool 10 . The shock absorber 100 can reduce the response (such as amplitude or intensity) corresponding to the resonant frequency of the machine tool 10 itself, so that chatter will not occur when the machine tool 10 works at the resonant frequency.

As shown in FIG. 1 , the shock absorber 100 is installed as close as possible to the rotating shaft 12 of the rotating module 11 to enhance the shock absorbing effect.

As shown in FIG. 2 , the horizontal axis represents the operating frequency f of the machine tool 10 , and the vertical axis represents the response R (displacement/force) corresponding to the operating frequency f. It can be seen from the figure that although the machine tool 10 has a specific resonant frequency fr, since the shock absorber 100 can reduce the response corresponding to the resonant frequency fr of the machine tool 10, the machine tool 10 equipped with the shock absorber 100 will be at a resonant frequency Working under fr will not cause resonance, thereby avoiding chatter. For example, the response Ra corresponding to the resonance frequency fr of the machine tool 10 itself is greatly reduced to the response Ra' after the shock absorber 100 is used, thereby avoiding the occurrence of chatter. Consequently, due to the design of the vibration damper 100 , the operating frequency f of the power tool 10 equipped with the vibration damper 100 does not have to avoid in particular the range of the resonance frequency fr.

As shown in FIG. 3 , the horizontal axis represents the rotation speed T of the machine tool 10 , and the vertical axis represents the cutting depth t corresponding to the rotation speed T. Inside the curve C (hatched area) is the processing stable area, and the area outside the oblique line is the unstable area. If the working point corresponding to the cutting depth t and the rotating speed T falls in the machining stable zone, it means that chatter will not occur; if the working point corresponding to the cutting depth t and the rotating speed T falls in the unstable zone, it means Chattering may occur. Due to the design of the shock absorber 100 , even if the operating point corresponding to the depth of cut t and the rotational speed T of the machine tool 10 falls in an unstable region, chattering can still be avoided. In this way, the machine tool 10 is not excessively restricted by the rotation speed T and the depth of cut t during operation.

Please refer to FIG. 4 , which is a cross-sectional view of the shock absorber 100 in FIG. 1 . The shock absorber 100 includes an outer cover 105, a connecting piece 110, a housing 115, a screw 120, a displacement adjustment piece 125, at least one first spring 130, at least one second spring 135, a mass 140, a driving mechanism 145, and an adapter 150 (shown in FIG. 1 ) and a controller 155 . Wherein the adapter 150 is selectively included in the shock absorber 100 , that is, in another embodiment, the shock absorber 100 may not include the adapter 150 .

The outer cover 105 and the connecting member 110 are respectively disposed at two opposite ends of the housing 115 . The connecting piece 110 is used to be directly fixed on the fixing base 13 of the machine tool 10 , or be indirectly fixed on the fixing base 13 of the machine tool 10 through an adapter 150 (as shown in FIG. 1 ). The screw rod 120 , the displacement adjusting member 125 , the first spring 130 , the second spring 135 and the mass block 140 can be disposed in the casing 115 to be protected by the casing 115 .

The screw 120 includes a first end 121 and a second end 122 . The first end 121 is rotatably connected to the connecting member 110 . For example, the first end 121 can be installed on a bearing 160 and connected to the connecting member 110 through the bearing 160 . The displacement adjusting member 125 is screwed to the screw rod 120 . For example, the displacement adjustment member 125 is screwed to the screw rod 120 , so that when the screw rod 120 rotates, the displacement adjustment member 125 is limited by the housing 115 and can only move along the adjustment direction D1 . The mass block 140 is located between the first spring 130 and the second spring 135 and connected to the first spring 130 and the second spring 135 respectively. The screw 120 passes through the mass block 140 , and the mass block 140 does not rotate with the screw 120 but only displaces. The first spring 130 is located between the mass block 140 and the displacement adjustment member 125 and connects the mass block 140 and the displacement adjustment member 125 . In this way, when the screw rod 120 rotates to drive the displacement adjustment member 125 to move along the adjustment direction D1, the deformation of the first spring 130 and the second spring 135 can be changed.

In one embodiment, the elastic constants of the first spring 130 and the second spring 135 are both nonlinear. In this way, when the deformations of the first spring 130 and the second spring 135 change, it means that the elastic constant of the first spring 130 and the elastic constant of the second spring 135 also change accordingly. By changing the elastic constant of the first spring 130 and the elastic constant of the second spring 135 , the resonance frequency of the shock absorber 100 itself can be adjusted. In this way, the elastic coefficient of the first spring 130 and the elastic coefficient of the second spring 135 can be adjusted to adjust the resonance frequency of the shock absorber 100 itself to the resonance frequency fr of the machine tool 10 itself, so as to prevent the machine tool 10 or the rotating module 11 from Flutter occurs, of course, the above examples are not limited to this.

In addition, the embodiment of the present invention does not limit the quantity of the first springs 130 and the quantity of the second springs 135 . The number of the first spring 130 can be one, two or more. When the number of the first spring 130 is one, the first spring 130 can be sleeved on the screw rod 120 (arranged around the screw rod 120 ). When the number of the first springs 130 is two, the first springs 130 can be arranged symmetrically. Similarly, the number of the second spring 135 can be one, two or more, and its arrangement can be similar to that of the first spring 130 , which will not be repeated here. In addition, the number of the first springs 130 and the number of the second springs 135 may be the same or different.

As shown in FIG. 4, the outer cover 105 has a through hole 105a. The second end 122 of the screw 120 passes through the through hole 105 a and protrudes from the outer cover 105 , so that the driving mechanism 145 can be connected to the second end 122 of the screw 120 outside the housing 115 . The driving mechanism 145 includes a transmission mechanism 1451 and a motor 1452. The motor 1452 can drive the transmission mechanism 1451 to drive the screw 120 to rotate, so as to drive the displacement adjustment member 125 to move along the adjustment direction D1, thereby adjusting the deformation and elastic coefficient of the spring. In one embodiment, the transmission mechanism 1451 is, for example, a reduction mechanism, such as a worm gear set. In detail, the transmission mechanism 1451 includes a worm wheel 1453 and a worm 1454 , wherein the worm wheel 1453 is fixedly connected to the second end 122 of the screw 120 , and the worm 1454 engages with the worm wheel 1453 to drive the screw 120 to perform deceleration.

The controller 155 is electrically connected to the motor 1452 to control the motor 1452 to drive the transmission mechanism 1451 to drive the screw 120 to rotate to adjust the deformation of the spring. The controller 155 can determine the displacement corresponding to the operating frequency when the rotating module 11 or the machine tool 10 vibrates according to a displacement-frequency relationship R1. The displacement-frequency relationship R1 can be pre-stored in the controller 155 or a storage unit (not shown). The relationship between displacement and frequency R1 is the corresponding relationship between the displacement of the displacement adjustment member 125 and the resonant frequency of the shock absorber 100 . For example, the displacement-frequency relationship R1 includes at least one set of correspondences, wherein the correspondences include a first displacement and a first resonance frequency. When the displacement adjustment member 125 is displaced by the first displacement amount along the adjustment direction D1, the resonance frequency of the shock absorber 100 itself changes to the first resonance frequency, so as to reduce the vibration of the machine tool 10 equipped with the shock absorber 100 at the first resonance frequency. Corresponding response, thereby avoiding flutter.

Please refer to FIG. 5A and FIG. 5B . FIG. 5A is a graph showing the relationship between the displacement and force of the displacement adjustment member 125 in FIG. 4 , and FIG. 5B is a graph showing the relationship between the working frequency and the response of the machine tool 10 in FIG. 4 .

As shown in FIG. 5A , points a, b and c represent different displacements of the displacement adjusting member 125 respectively, which correspond to different forces of the spring. The slope of the graph of FIG. 5A represents the spring constant of the spring. The slopes of points a, b and c are Sa, Sb and Sc, respectively. The slopes Sa, Sb and Sc are different, it can be seen that the spring of the embodiment of the present invention provides a non-linear elastic coefficient. As shown in FIG. 5B , points a, b, and c correspond to different resonance frequencies. It can be seen that changing the displacement of the displacement adjustment member 125 can change the resonance frequency of the machine tool 10 .

FIG. 6 is an equivalent system diagram of the machine tool 10 provided with the shock absorber 100 of FIG. 1 . The first spring 130 and the second spring 135 can be equivalent to a spring 130', which has an elastic coefficient Ks, and the mass block 140 has a mass Ms, and the first spring 130 and the second spring 140 themselves have damping, which can be equivalent to The damping Cs. In addition, the mass Mt, the elastic coefficient Kt, and the damping Ct are equivalent systems of the machine tool 10 itself. The resonance frequency of the overall system in FIG. 6 can be changed by adding the elastic coefficient Ks, mass Ms and damping Cs of the shock absorber 100 itself. For example, if the resonance frequency synthesized by the elastic coefficient Ks, mass Ms, and damping Cs of the shock absorber 100 itself is substantially equal to the resonance frequency fr of the machine tool 10 itself, then the shock absorber 100 will , can reduce the response R corresponding to the resonance frequency fr of the machine tool 10 itself, as shown in FIG. 2 .

FIG. 7 is a flowchart of a semi-active vibration reduction method according to an embodiment of the present invention. In step S110 , the sensor 14 (shown in FIG. 1 ) senses the processing condition of the rotating module 11 or the machine tool 10 , wherein the rotating module 11 is equipped with a shock absorber 100 , as shown in FIG. 1 . The sensor 14 is disposed on the fixed base 13 of the rotating module 11 and disposed close to the rotating shaft 12 to increase the accuracy of sensing vibration. For example, the sensor 14 can be disposed on the lower surface 13 b of the fixing base 13 so as to be close to the rotating shaft 12 . In addition, the sensor 14 is electrically connected to the controller 155 to transmit a sensing signal to the controller 155 . The sensor 14 is, for example, a microphone, which can detect the audio when the rotating module 11 rotates, so that the controller 155 can analyze whether vibration occurs.

In step S120, the controller 155 determines whether the rotary module 11 or the machine tool 10 vibrates. If yes, go to step S130; if not, go back to step S110.

In step S130 , according to the displacement-frequency relationship R1 , the displacement corresponding to the operating frequency (or resonant frequency) when chatter occurs is determined. The displacement-frequency relationship R1 can be pre-stored in the controller 155 or a storage unit (not shown). The relationship between displacement and frequency R1 is the corresponding relationship between the displacement of the displacement adjustment member 125 and the resonant frequency of the shock absorber 100 .

In step S140, the controller 155 controls the operation of the motor 1452 to drive the screw 120 of the shock absorber 100 to rotate, and then drives the displacement adjustment member 125 to displace the displacement, so as to adjust the resonance frequency of the shock absorber 100 itself to the point where chatter occurs. operating frequency. In this way, if the machine tool 10 equipped with the shock absorber 100 operates at the operating frequency, the response will be reduced, thereby avoiding chattering.

In summary, the shock absorber of one embodiment of the present invention can be installed on a machine, and can semi-actively adjust its own resonant frequency, so as to reduce the response (such as amplitude or strength) of the machine when it works at the resonant frequency. , so as to avoid excessive response causing damage to the machine or negatively affecting the working quality of the machine.

In summary, although the present invention has been disclosed in conjunction with the above preferred embodiments, they are not intended to limit the present invention. Those skilled in the art to which the present invention belongs can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be defined by the appended claims.

Claims (9)

1. A shock absorber for being mounted on a rotating module, the shock absorber comprising: screw; The displacement adjustment part is screwed to the screw rod; at least one first spring; at least one second spring; a mass block, located between the first spring and the second spring, connected to the first spring and the second spring respectively, and pierced by the screw rod; a housing for accommodating the screw, the displacement adjusting member, the first spring, the second spring and the mass block; an outer cover attached to one end of the housing; and a connecting piece connected to the other end of the casing and used to be fixed on the rotating module; Wherein, the first spring is located between the mass block and the displacement adjustment member and is connected to the mass block and the displacement adjustment member, and the second spring is located between the mass block and the outer cover and is connected to the mass block and the outer cover. cover, and the elastic constants of the first spring and the second spring are nonlinear. 2. The shock absorber of claim 1, further comprising: The adapter is fixed on the rotating module. 3. The shock absorber according to claim 1, wherein a first end of the screw rod is rotatably connected to the connecting member; the outer cover has a through hole, and a second end of the screw rod passes through the through hole and protrude from the outer cover. 4. The shock absorber of claim 3, further comprising: The driving mechanism is connected to the second end of the screw rod. 5. The shock absorber of claim 4, wherein the drive mechanism comprises: a transmission mechanism that engages the screw; and The motor is used to drive the transmission mechanism to drive the screw to rotate. 6. The shock absorber of claim 4, further comprising: The controller is used to determine a displacement corresponding to an operating frequency when the rotating module chatters according to a relationship between displacement and frequency, and controls the driving mechanism to drive the screw to rotate, so that the displacement adjustment member is displaced The amount of displacement. 7. The shock absorber as claimed in claim 6, wherein the relationship between the displacement and the frequency is a corresponding relationship between the displacement of the displacement adjusting member and the resonant frequency of the shock absorber. 8. A semi-active vibration reduction method, comprising: Sensing the processing condition of a rotating module, wherein the rotating module is equipped with a shock absorber as claimed in claim 1; Judging whether the rotating module flutters; If the rotating module vibrates, according to a relationship between displacement and frequency, determine a displacement corresponding to an operating frequency when the vibrating occurs; and The screw rod that drives the shock absorber rotates to drive the displacement adjusting member to displace the displacement amount. 9. The semi-active vibration damping method according to claim 8, wherein the relationship between the displacement and the frequency is a corresponding relationship between the displacement of the displacement adjusting member and the resonant frequency of the shock absorber.